Clam-shell and bucket control system



March 12, 1957 A. o. HELLERUD CLAM-SHELL AND BUCKET CONTROL SYSTEM Filed July 20, 1954 IZfVENTOR Arbhur O. Hellerud United States Patent CLAM-SHELL AND BUCKET CONTROL SYSTEM Arthur 0. Hellerud, Pierce, Idaho Application July 20, 1954, Serial No. 444,421

3 Claims. (Cl. 214 657) The present invention relates broadly to hoisting and earth-moving equipment and specifically to a control system which permits the precise manipulation of a suspended clam-shell or grab bucket.

In most excavating and earth working equipment, a cable or line extends from near the operator to the bucket or grappling tool which is at the end of one or more steel ropes and swung from a movable boom. In the control of the bucket, the operator becomes adept at swinging the boom from side to side in short movements to start the bucket swinging. The swinging movement of the bucket, due to the suspension by the steel ropes, permits or causes the bucket to take bites from the material handled in several positions of the bucket. Inexperienced operators, with the present invention may attain the same ends and with less skill control the bucket or claim-shell accurately and with precision movements, without resorting to swinging the boom which is at least a time-consuming device and often the cause of accidents. Frequently an operator, watching the bucket, will swing the boom into contact with wires.

The principal object of the present invention is to provide a device which can be attached to every type of a hoist apparatus and will assist the operator to have instant and finger-tip control of the apparatus which is suspended and is used to hoist, dig, demolish or otherwise work earth, rubble or transfer materials.

Another object of the present invention is to provide a device which is automatic in operation to the degree that it prevents the cable or line which attaches to the bucket or clam-shell from swinging freely in all positions of the bucket or shell, and is ready instantly for sway control or precise positioning of the shell or bucket.

These and other objects and advantages of the present invention will be readily apparent from the following .description when considered in connection with the annexed drawings, in which:

Figure 1 is a diagrammatic view in side elevation of a typical piece of earth moving equipment with the present invention in place, and

Figure 2 is a schematic drawing of the parts of the present invention.

Referring in more detail to the drawings, in which like reference numerals indicate like parts throughout the several views, it will be seen that the present invention consists of a motor which operates on compressed air from a supply tank, indicated in Figure 1 at 11 and compressed by the compressor 12., here illustrated more or less schematically.

The motor It is installed on the boom 13 of the excaclam-shell.

the drum 22 on which the steel rope 23 is wound for hoisting the clam-shell 18.

A conduit 24 connects the air motor 10 to the tank 11, and of course, includes such swivel connections necessary in moving the boom 13, although such connections are not here shown.

Electrical connections 32 from a source, not shown, connect the switches 19 and 20 to each of the two solenoid control valves 25 and 26, the first of which is disposed in a by-pass conduit 27 and controls the admission of air to one side of the air motor 10. A pressure-reducing valve 28 in the line 29 permits a steady flow of low pressure air to the same side of the motor for the purpose to be later explained.

Another conduit 30 leads air under high pressure to the second solenoid valve 26 which controls the admission of air to the other side of the motor 10. A port 31 exhausts the spent air to the atmosphere.

In operation, a certain amount of air is constantly fed to the air motor 10 to keep the drum 15 turning and to keep the line 16 tight enough to keep off the ground and without any tangle. As the clam-shell rises and falls, the line 16 pays out, the drum 15 turning against this low air pressure, with the air motor 16 not damaged by this action of the drum.

When the claim shell 18 is to be turned or swung, opening of the valve 25 will admit high pressure air to revolve the drum under positive power, pulling the claim-shell on the one side into whatever position is intended by the operator.

The other valve 26 when opened will permit high pressure air to be admitted to the other side of the air motor 10, reversing the rotation of the drum, in such cases where the slight drag of the line 16 due to the constant low air pressure prevents the desired placement of the The admission of high pressure air to both sides of the air motor 10 simultaneously, will lock the air motor and this action is possibly used whenever the claim-shell has been pulled toward the operator and it is desired to hold it there, without further pulling.

The air motor 10, of conventional make, has an exhaust port 31, and may be geared to the drum or connected by direct drive, as here illustrated in schematic form.

While only a single embodiment and preferred form of the present invention has been described and illustrated herein, many other embodiments are contemplated and many changes and modifications may be made without departing from the scope of the invention as defined in the appended claims.

Having thus set forth and disclosed the nature of this invention what is claimed is:

1. A control system for use with a machine having a suspended clam-shell or the like, comprising at least one air motor operable in opposite directions adapted and arranged to be supported on said machine, a drum rotatably drivable by said air motor in either direction, a line adapted and arranged to be connected at one end to said claim-shell and to be wound on said drum at its other end, conduits connecting each side of said air motor to a source of air under pressure, and means operable to control the flow of air to each side of said air motor for control thereof whereby the clam-shell may be pulled toward said air motor or whereby air pressure may be equalized on both sides of said motor to hold said drum against rotation in either direction.

2. A control system for use with a machine having a suspended clam-shell or the like, comprising at least one air motor adapted and arranged to be supported on said machine, a drum rotatably drivable by said air motor in either direction, a line adapted and arranged to be connected at one end to said clam-shell and to be wound on said drum at its other end, conduits connecting each side of said air motor to a source of air under pressure, another conduit connecting one side of said motor to a source of air having a pressure less than that available to said first-named conduits whereby said air motor tends to keep rotating in one direction, and valve means in said first named conduits to control the air admitted to said motor on either side thereof whereby positive power may be applied to said drum in one direction of rotation to pull said line and in the other direction to reverse said drum against the rotation due to the low pressure air.

3. A control system for use with a machine having a suspended claim-shell or the like, comprising at least one air motor adapted and arranged to be supported on said machine, a drum rotatably drivable by said air motor in either direction, a line adapted and arranged to be con- 1 nected at one end to said clam-shell and to be wound on said dr-um at its other end, conduits connecting each side of said air motor to a source of air under pressure, another conduit connecting one side of said motor to a source of air having a pressure less than that available to said first-named conduits whereby said air motor tends to keep rotating in one direction, and means including electrical control switches and solenoid valves disposed in said first named conduits to control the air admitted to said motor on either side thereof whereby positive power may be applied to said drum in one direction of rotation to pull said line and in the other direction to reverse said drum against the rotation due to the low pressure air.

References Cited in the file of this patent UNITED STATES PATENTS 2,588,037 Orton Mar. 4, 1952 

